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Book review: A Short History of Humanity: A New History of Old Europe by Johannes Krause

I read this book the other day and it’s worth reviewing in some detail.

  • Krause, J., & Trappe, T. (2022). A short history of humanity: A new history of old Europe. Random House Trade Paperbacks.

If you are familiar with David Reich’s excellent 2018 Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past book, this will be very similar to you. It’s more popsci than Reich’s book, foregoing details about divergence tests and focusing more on telling the story of Europeans, but it’s still good. It’s a shorter book (288 pages vs. 355), but that’s also because it is mainly about Europe, not all of the world. You won’t find any lengthy discussions about the Indian subcontinent or Chinese genomics in this book. Instead you will find these 10 chapters:

  • Chapter 1: A New Science Is Born
  • Chapter 2: Persistent Immigrants
  • Chapter 3: Immigrants Are the Future
  • Chapter 4: Parallel Societies
  • Chapter 5: Single Young Men
  • Chapter 6: Europeans Find a Language
  • Chapter 7: Refugee Ships on the Mediterranean
  • Chapter 8: They Bring the Plague
  • Chapter 9: New World, New Pandemics
  • Chapter 10: Conclusion: The Global Melting Pot

The TL;DR of the book is that it tells the story of how archaeologists used to think about ancient Europeans based on cultural remains — pottery, metal works, buildings, hunting tools — and then how ancient genomics revolutionized the thinking and turned over a few well accepted ideas. So it’s a story of the first human migrating into Europe, Neanderthals, their mixing with regular Homo Sapiens Sapiens, the Denisovans, isolate groups like the Basque and Sardinians. A lot of focus is on the invasions by the Anatolian farmers and the Indo-Europeans (Aryans), battle axe people, how genetic distances work, and so on. Generally, speaking, a useful introduction book that people without a science background can appreciate.

Some of the chapter titles of the chapters are somewhat woke sounding, but most of the content is not. The main exception is chapter 10. I take it the author — I assume Krause did most of the writing and Trappe fixed up the prose — had to do some level of woke signaling, and he put most of it in the last chapter. The author, by the way, is a prominent German geneticist with focus on ancient DNA. Or as the authors flatteringly describe themselves:

Two authors have contributed to this book. The first is Johannes Krause, who assumes the role of first-person narrator from the next chapter onward. He is one of the most established international experts in the field of archaeogenetics (for reasons of modesty this passage was written by the second author) and is director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. His coauthor, Thomas Trappe, was tasked not only with compressing Krause’s knowledge into a compact narrative but also with placing it in a contemporary context and framing it within ongoing political debates. Trappe has previously collaborated with Krause several times; he has also reported on nationalism and contemporary populist ideas. Over the course of many conversations, both authors realized they wanted to write a book that would bring together science and up-to-the-minute debates.

Naturally, you might think that an academic and a journalist with focus on “nationalism and contemporary populist ideas” doesn’t make for a very good combo, you would be partially right. But let’s first go over the good stuff. This is mostly a good book, and I recommend it. Block quotes are from the book unless otherwise specified:

This has nothing to do with our “true origins.” Take the migration period, for example, a time in European history that certainly witnesses a lot of genetic exchange between various European populations, but no fundamental genetic shift. You have to go back almost 5,000 years into the past to find the last major migration movement that altered the DNA of all Europeans. The DNA of people who came from the Eastern European steppes 5,000 years ago is still one of the three dominant genetic components on the continent today. The other two originate from early hunter-gatherers and from farmers who migrated there from Anatolia. The genetic ratio of these three archaic populations can be quantified through DNA testing in every person who has European roots. By now, there are numerous companies offering this type of service.

It’s doubtless interesting to discover whether you have more in common genetically with hunter-gatherers, early farmers, or steppe populations. But most commercial testing companies can offer little more than folklore, because these different components tell us solely about our genetic ancestry; they often tell us nothing about our predispositions. Even if you tested the two most genetically different people on Earth, they would still share 99.8 percent of their DNA. In fact, we differ from Neanderthals in less than half a percent of our genome. So when we talk about genetic shifts, we’re really only talking about changes to a tiny fraction of DNA. Populations that lived in close geographical and genetic proximity, such as the French and the Portuguese, are thus only distinguishable through genome-wide analysis.

They forget about the current population replacement, which is soon going to be on the same order of magnitude as that of the Anglo-Saxon settlers in England. They do discuss the latter, so it would have been useful for them to discuss the parallels with modern migration-by-invitation.

Krause is not quite right that the ancestral proportions do not tell us anything interesting. There is already published research on what these ancestral proportions predict (Marnetto 2022):

The contemporary European genetic makeup formed in the last 8,000 years when local Western Hunter-Gatherers (WHGs) mixed with incoming Anatolian Neolithic farmers and Pontic Steppe pastoralists.1, 2, 3 This encounter combined genetic variants with distinct evolutionary histories and, together with new environmental challenges faced by the post-Neolithic Europeans, unlocked novel adaptations.4 Previous studies inferred phenotypes in these source populations, using either a few single loci5, 6, 7 or polygenic scores based on genome-wide association studies,8, 9, 10 and investigated the strength and timing of natural selection on lactase persistence or height, among others.6,11,12 However, how ancient populations contributed to present-day phenotypic variation is poorly understood. Here, we investigate how the unique tiling of genetic variants inherited from different ancestral components drives the complex traits landscape of contemporary Europeans and quantify selection patterns associated with these components. Using matching individual-level genotype and phenotype data for 27 traits in the Estonian biobank13 and genotype data directly from the ancient source populations, we quantify the contributions from each ancestry to present-day phenotypic variation in each complex trait. We find substantial differences in ancestry for eye and hair color, body mass index, waist/hip circumferences, and their ratio, height, cholesterol levels, caffeine intake, heart rate, and age at menarche. Furthermore, we find evidence for recent positive selection linked to four of these traits and, in addition, sleep patterns and blood pressure. Our results show that these ancient components were differentiated enough to contribute ancestry-specific signatures to the complex trait variability displayed by contemporary Europeans.

Granted, this research came out after the book was published in 2021 (preprint posted in August 2021), but there may be other research that this. The results are difficult to summarize in a figure and though they provide one, even I don’t know how to easily interpret it, so I won’t post it here. But in their words they found:

WHG ancestry in present day individuals is linked to lower cholesterol levels, higher BMI, and putatively contributed brown hair and light eye color to the contemporary Estonian population. This last association has been previously described based on the HERC/OCA2 haplotypes found in ancient WHG samples.5,23 In addition, loci associated with these features also appear to have undergone selection in Estonians. Other region-specific associations for this ancestry include decreased hip circumference and increased caffeine consumption and heart rate.

An enriched Yamnaya ancestry is linked to a strong build, with tall stature (in agreement with previous studies6,8) and increased hip and waist circumferences, both at genome-wide and region-specific levels, but also to black hairs and high-cholesterol concentrations when focusing on candidate regions. The associations of Yamnaya and WHG ancestries to respectively higher and lower cholesterol levels, together with the observed signatures of selection at loci connected to cholesterol and BMI, add a new component to our understanding of post-neolithic dietary adaptation7,30,31 with potential implications to disease risk and outcomes in present-day populations.

Anatolia_N enrichment in trait-related genomic regions is connected with a reduced BMI-corrected waist-to-hip ratio, reduced BMI, light (but not green) eyes and fair hair, increased age at menarche, and reduced heart rate. Notably, covA(i,Anatolia_N) has a substantial weight only in IC2, the single IC that reaches significance when predicting heart rate, suggesting a prominent role for this ancestry in determining this trait.

Finally, the Siberian ancestry is connected with dark hair pigmentation, higher heart rate, lower caffeine consumption, and most prominently, green eye color and lower age at menarche. Importantly, while the results connected to the Siberian ancestry are not of broad applicability to all European populations, covA(i,Siberia) and relative ICs received effect-sizes with mixed significance in all the previous traits except for age at menarche and pigmentation, suggesting that other ancestries might have a larger impact. In other words, we do not find other phenotypes that can be best explained by similarity with Siberia, implying that the presence of this ancestry in the Estonian genome does not significantly affect the inference based on the other, pan-European ancient components.

Some of these are a bit difficult to believe — light hair from Anatolian farmers?? — but overall this illustrates that one can indeed figure out where the European constellation of phenotypes came from in terms of ancient admixture, and thus also predict the phenotypes of any given modern human with some small but above chance level of accuracy (small because Europeans do not vary a lot in their ancient ancestry proportions within some ethnic group). This kind of research has also previously been done for Neanderthal admixture (Gregory 2021). The method that the mainstream researchers use here is about the same as that we use to study the effects of racial genetic ancestry on modern humans for intelligence (Kirkegaard 2019, Lasker 2019, Fuerst 2021). Theoretically, you just do a linear regression with the ancestry proportion(s) as the independent variables, and then you predict the value of the phenotype when ancestry goes from 0 to 100%.

man’s oldest friend

One of the hunter-gatherers’ greatest innovations—one that is still part of our twenty-first-century lives—was the dog. For hunters, dogs were indispensable. For many of us today, they’re members of the family. It’s estimated that wolves were first domesticated 20,000 to 15,000 years ago, though whether this occurred on several continents in parallel or in Ice-Age Europe first is still up for debate. The oldest dog in Germany was found in a double grave in Oberkassel, a suburb of Bonn, where it was interred around 14,000 years ago beside a fifty-year-old man and a woman half that age. The grave goods buried with them included teeth from another dog, which indicates that the animal had great significance for them.

Whether his two owners looked like him—the way people these days like to say owners look like their dogs—we can only guess. Genetically, on the other hand, dogs have indeed grown more similar to humans. Like us, they can digest carbohydrates much better than their wild ancestors. Modern-day dogs have far more copies of the gene regulating the production of the enzyme amylase, which is used to digest foods such as rice and potatoes. The same mutations took place in humans as our diets came to include more carbohydrates. Unlike chimpanzees, Neanderthals, and Denisovans, who only had two copies of the amylase gene, most people today have between ten and twenty copies—more or less the same number as our four-legged friends. This parallel mutation in dogs and humans indicates that dogs have long been not only our most faithful companions but also our most convenient way to dispose of leftovers.

That’s very interesting. I was not aware of such existing copy-number variation. Does it differ enough by ancestry that one can use it as a proxy for farming history? Recent debates in Chinese genomics have centered on the role of rice vs. wheat farming in shaping the differences between Han Chinese in different areas. E.g., Large-Scale Psychological Differences Within China Explained by Rice Versus Wheat Agriculture (Talhelm 2014):

Cross-cultural psychologists have mostly contrasted East Asia with the West. However, this study shows that there are major psychological differences within China. We propose that a history of farming rice makes cultures more interdependent, whereas farming wheat makes cultures more independent, and these agricultural legacies continue to affect people in the modern world. We tested 1162 Han Chinese participants in six sites and found that rice-growing southern China is more interdependent and holistic-thinking than the wheat-growing north. To control for confounds like climate, we tested people from neighboring counties along the rice-wheat border and found differences that were just as large. We also find that modernization and pathogen prevalence theories do not fit the data.

The first author Talhelm also provides a review of this work up to 2020. I am not too familiar with it, but generally think that farming history should have evolutionary implications and thus probably impact modern humans.

With regards to the amylase variation, research has already established that this variation has notable effects on functioning, but does not seem to associate much with e.g. BMI (Aktinson 2018). Neither does it seem to relate to risk of death or interact with starch intake to predict death (Li 2023). This is somewhat surprising, so maybe we need to reevaluate some ideas in this domain. Still, there are some papers finding that variation does predict some measures of obesity and seems to interact with ethnicity, at least in one study, between Arabs and Persians living in Qatar (Rossi 2021). Back to the book:

the neolithic revolution brought into close quarters two populations that were fundamentally—and visibly—genetically different. The hunter-gatherers, long established in Europe, had much darker skin than the Anatolian migrants. It’s not immediately obvious why people from the warmer south would have lighter skin than those who had been living in the chilly north. Because people with more skin pigment are better protected from carcinogenic UV rays, the darkest skin types are found today below the equator in Central Africa. People in northern regions facing the opposite problem, a deficit of sunlight, have less pigment so they can absorb enough UV radiation to synthesize vitamin D. This is why some countries fortify foods—usually milk—with vitamin D, or require their long-suffering children to drink cod liver oil. In Germany, the Robert Koch Institute recommends people increase their consumption of vitamin D. Those with darker skin, it adds, are more likely to be deficient.

Australia, which has a majority population descended from British émigrés who arrived less than a century ago, also happens to have the highest rate of skin cancer on the planet. A third of Australians will be diagnosed with skin cancer at some point during their lifetime. As far as evolutionary biology is concerned, people with pale skin shouldn’t live near the equator—or they should at least drag out the move for a millennium or two, to give their skin some time to genetically adapt. For it can adapt. The indigenous peoples of the Americas have much darker skin near the equator than at the southern tip of South America—although both are descended from the same population, which emigrated to the Americas roughly 15,000 years ago. In 10,000 years’ time, Australia’s European descendants will probably have a skin tone similar to that of the Aborigines, who arrived there much earlier, assuming there is no further immigration from Europe—and no SPF 50 sunscreen.

It’s a curious argument. At first, it looks like Krause doesn’t understand how selection works. Human skin color will only evolve to be darker in Australia if that actually has a selective advantage. Since almost all skin cancer occurs later in life and is usually not fatal, the selection strength is near-zero insofar as mortality is concerned. Here’s some Australian data:

  • More than two in three Australians will be diagnosed with skin cancer in their lifetime.1
  • About 2,000 Australians die from skin cancer each year.2

About 160k people die per year in Australia, which means that skin cancer kills some 2000/160k=1.25%. To be sure, I checked the Australian government’s published list of top causes of death:

Skin cancer does not even appear in the top 20, as one would expect based on the estimated 1.25% of all deaths (cause number 20 kills 1.4%). But if age of onset is relatively young, it could still have some minor selection effect. However, “In 2018, the mean age for melanoma diagnosis was 66 years among men and 62.3 years among women.”. In fact, depending on the other effects of skin color on fertility, selection might be towards lighter skin insofar as men find this attractive. Peter Frost has written a lot about this topic. I couldn’t find any results relating skin color to fertility in Australians.

A second reading of Krause’s statement, then, might be that the future “Australia’s European descendants” will be heavily admixed with non-Europeans with darker skin color and thus have darker skin too. Of course, that is a likely outcome given current migration projections, but that’s not really what he seems to be saying.

Europe’s hunter-gatherers were blue-eyed as well as dark-skinned. Although light skin gradually became the norm across Europe, blue eyes remained common even after the wave of migration from Anatolia. We still don’t know why. By default, the iris is dark, so lighter eyes are always the result of mutations that lead to reduced pigmentation. Lighter eyes provide no obvious benefit, while darker ones seem to be less sensitive to light. Yet this does not explain why light eyes in Europe are far more frequent today than they would be if they were a by-product of chance. The most plausible suggestion is that people with blue eyes had better reproductive prospects. Blue eyes may simply have been considered beautiful. Genetic sequencing reveals the number of people with blue eyes declined following the influx of Anatolian farmers—then later climbed back up.

Blue eyes, incidentally, doesn’t necessarily mean blue like Paul Newman’s eyes. They’re just less pigmented, encompassing everything on the spectrum from grayish blue to green, and green eyes simply contain a mixture of blue and brown pigment. The same mutation can thus produce very different eye colors. In terms of skin tone too, there is an infinite palette of shades between light and dark. Although the mutations responsible for lighter skin do not seem to have appeared in the genes of Central European hunter-gatherers, we shouldn’t attach too much weight to that. Unfortunately, this is exactly what has happened in recent years, for instance when the DNA of “an ancient Briton” was decoded and references were made to his skin being as dark as that of modern-day West Africans. Such claims tend to be seized upon by the media and used to make wild generalizations. In fact, we do not know how dark-skinned the ancient hunter-gatherers were. The inheritance of skin color is highly complex and cannot be explained by single mutations alone. Whether early Europeans looked like modern-day people from Central Africa, or perhaps like people from the Arab world, is still unclear. All we can say for sure is they didn’t carry any mutation we know of that results in light skin, so it’s highly likely they had darker skin than contemporary Europeans.

If we look back further in human history, we see that dark skin was also an adaptation. Our cousin, the chimpanzee, has light skin under its dark coat. When humans shed hair, our skin evidently adapted to protect our exposed bodies from the sun. For this reason alone, using skin color to justify some sort of social hierarchy is absurd—unless those with light skin want to lay claim to a special genetic bond with chimpanzees.

Oh no, a stab at light skin color supremacy! But it is Krause’s own people — left-wing academics — who are obsessed with skin color. One can find endless numbers of books like Pigmentocracies: Ethnicity, Race, and Color in Latin America (2014). You can also see why that is the case. By focusing on skin color, one can talk about the supposed discrimination that happens because of this, and thus the unfair social differences (the theory is called colorism). From a commonsense hereditarian perspective, skin color is mostly a distraction. It correlates with ancestry (when groups are unequal in skin color), but is otherwise not of too much significance in explaining social status or intelligence gaps. We have shown this fact repeatedly in studies. When a regression model includes both genetic ancestry and skin color, skin color no longer predicts much or anything of note (Lasker 2021, Fuerst 2021, Kirkegaard 2018). This kind of finding is impossible in the colorism model. So far not a single colorism advocate has taken note of such contrary evidence. I predict that will continue to be the case for years to come.

The average person today probably doesn’t much care about when and why people in particular regions began drinking from certain types of cups. For archaeologists, however, it is a long-standing and politically charged question. Early twentieth-century archaeologists and scientists with connections to the Nazis argued that a people with a shared culture always constituted a single Volk—meaning they had common DNA. The implication was that superior cultural technologies went hand in hand with genetic superiority; descendants of the “Battle Axe culture,” for example, could claim they had a genetic right to power and control. These cultural, linguistic, and ethnic theories carried serious political baggage in German-language archaeology after the Second World War and were roundly condemned, replaced by the notion that cultures spread not through migration, conquest, and subjugation but through cultural exchange between populations. The idea that there were massive waves of migration into Europe and that these engendered large-scale cultural shifts thus proved controversial. Nonetheless, the genetic data regarding the Neolithic Revolution—and particularly regarding migration from the steppes—is unambiguous. It has been quite a headache for many archaeologists. Our analyses of the spread of Bell Beaker pottery into the Iberian Peninsula and Great Britain reveals that the debate is not black and white: cultural change often involves migration, but migration isn’t a necessary component of cultural transmission.

In other words, Krause admits that leftist politics among academics caused them to bias the evidence on replacement vs. cultural copying in archaeology. He even shies away from mentioning the name of the person who originated the replacement ideas: Gustaf Kossinna (28 September 1858 – 20 December 1931). He’s not mentioned anywhere in the main text, but some of his works are cited in the references. He looks pretty cool:

Wikipedia admits the same bias:

Along with Carl Schuchhardt he was the most influential German prehistorian of his day, and was creator of the techniques of settlement archaeology (German: Siedlungsarchaeologie).[1] His nationalistic theories about the origins of the Germanic peoples and Indo-Europeans influenced aspects of National Socialist ideology. Though politically discredited after World War II, Kossinna’s methodological approach has greatly influenced archaeology up to the present day.[a]

In the years following World War II, Kossinna’s theories of settlement archaeology were widely dismissed as pseudoscience. Recent discoveries in archaeogenetics have prompted a renewed discussion of Kossinna’s legacy and the significance of migration in prehistory.[b][c][2][3]

Poor Kossinna wasn’t even involved with the Nazis much, dying too early, in 1931, 2 years before Hitler took power. It took some 60+ years for the political bias of scientists against his correct ideas to be countered by superior evidence. In other words, science may be self-correcting, but it can take a long time when there is motivated resistance (Cofnas 2015).

many years’ work, and plenty of debate, led my colleagues and me to develop a new hybrid theory on the origin of Indo-European. For our model, we used genetic data about the waves of European migration during the Stone and Bronze Ages and drew on a method that allowed us a glimpse of our linguistic past. We incorporated techniques usually used in genetics, on the basis that what’s true for DNA is true for languages as well: they mutate with relatively consistent frequency. A geneticist can calculate from the DNA of two individuals when their most recent common ancestor was alive. In linguistics we can take two closely related words—the German Leiter, let’s say, and the English “ladder”—and work backward, figuring out how many steps there must be between the two variants and their single word of origin. These rates of mutation were calculated for thousands of words from numerous Indo-European languages, to produce a family tree that shows when the various languages branched off from one another. Its shape often mirrors the family tree of human populations: German, Danish, and English, for example, have more recent common ancestors than German and Italian.

Russell Gray, my colleague at the institute, was able to extend the linguistic family tree much further into the past than the first written sources of Indo-European. Together with his colleagues he analyzed the differences between the oldest known Indo-European languages—Mycenaean, Hittite, Ancient Greek, and Ancient Latin—and worked out how often they must have mutated since they’d diverged. The most recent common ancestor of all Indo-European languages, according to their calculations, was spoken roughly 8,000 years ago.

This figure has been public knowledge since 2003 and strongly suggests that Indo-European migrated west with the Anatolian farmers. Yet genetic data unearthed in recent years has refuted this thesis. It’s clear that Indo-European languages were spoken not only in Europe but also in India, Afghanistan, and Pakistan. While it’s true that agriculture spread both west and east from the Fertile Crescent 8,000 years ago, if Indo-European originated during this period then it follows that people in the east as well as the west would have spoken the same or very similar languages, which they then exported in both directions. Until recently, there was no evidence to the contrary; after all, the Fertile Crescent represented a homogenous cultural milieu between present-day Israel and Iran. Yet, as we now know, genetic data suggests that the eastern and western populations of the Fertile Crescent were two fundamentally different groups—groups as different as modern-day Europeans and Chinese—and must have diverged much more than 11,000 years ago; the same must be true of their languages. The origins of Indo-European must therefore date back at least 11,000 years, not 8,000, making the Anatolian theory moot. Proponents of the steppe theory had a similar problem, because their model was equally irreconcilable with the evidence that the most recent common ancestor of all Indo-European languages existed 8,000 years ago. Though they assumed that what’s known as the Maikop culture, located in the region between the Black and Caspian Seas, transmitted Proto-Indo-European eastward and westward, that culture dates back no more than 6,000 years.

The idea of a molecular clock is popular in genomics, but linguists generally don’t like it the analogous idea in their domain. One eminent historical linguistics author, Lyle Campbell, wrote in a textbook:

Glottochronology has given linguistics a bad reputation with some other prehistorians. For example, many archaeologists were initially very happy to embrace its dates, and they frequently proposed interpre- tations of the prehistory of different peoples and areas which relied on glottochronological dates and attempted to correlate them with other sources of information on prehistory. However, as archaeologists came to find out about the problems of the method and the unreliability of the dates, some felt deceived and came to believe that linguistics had nothing to offer them. This is unfortunate, for though glottochronology proved misleading, other areas of historical linguistics have an important role to play in the study of prehistory in general (as shown in Chapter 15). In summary, glottochronology is not accurate; all its basic assumptions have been severely criticised. It should not be accepted; it should be rejected. (For references and discussion, see Campbell 1977: 62-5.) For subgrouping, only shared innovations prove reliable, if the cautions about independently occurring changes and possibly inaccurate reconstructions are kept in mind. The best-defined subgroups are those which are based on a number of shared innovations of the type which are not likely to happen independently or to be diffused across language boundaries.

Modern authors seem to disavow the specific label (glottochronology), but the method is more or less the same (Gray 2011).

Genetic analyses have given us a highly accurate picture of what happened during the Neolithic Revolution, which began in Europe 8,000 years ago. Archaeologists had known for ages that people had begun to farm around that time. Though they had their detractors, many researchers theorized that this revolution was less a major upheaval than a fluid transition. Agriculture, they argued, was carried like a torch from the Near East to every corner of Europe, bringing new knowledge and sowing the earth with grain. With the genetic evidence we’ve gathered, however, we can say with certainty that agriculture was brought to Europe from the Near East by large families of migrants who sidelined established populations. Because old and new populations had virtually no contact for centuries, it does make sense to talk about cultural suppression. The Neolithic period is a prime example of the decline of the “West” and the triumph of the “East”—although at this point the West was an extremely modest society in which people lived as nomads in the woods and grasslands, while migrants from the Near East imported a significantly more advanced lifestyle.

While the Neolithic Revolution can still be considered a largely peaceful—albeit imposed—takeover of Europe by foreign populations, this picture becomes altogether more complex when we reach the second major wave of migration, which began around 5,000 years ago. In the Neolithic period, migrants from the Near East found themselves on a sparsely populated continent that offered both them and the established population enough space and food for all. Three thousand years later, however, when the new Europeans arrived from the steppes, they encountered a population weakened—probably by the plague they’d imported. The history of immigration in the Bronze Age is thus an example of migrants who brought either disease and death or violence and destruction in their wake.

Europeans today are therefore the product of large-scale patterns of movement stretching back millennia and encompassing near-constant interaction, suppression, struggle, and deep suffering. There is no reason, however, to view contemporary Europeans as descended from the victims of these upheavals. If you look at the settlement of Europe as the drama it so often was, then at least 70 percent of its cast are descended from the antiheroes: the migrants who arrived on the continent and subjugated it 8,000 and 5,000 years ago. The genetic makeup of the hunter-gatherers who had previously dominated is now in the minority, although it’s still one of the three genetic pillars of Europe.

Genetic data offers us a much more detailed picture of the flow of migrants thousands of years ago, but its gaps leave plenty of room for interpretation. This much is clear: the early history of migration in Europe does not support either romanticization or fatalism. No, migration was rarely entirely peaceful, and yes, without it the continent would not be as advanced as it is today. A prehistoric Europe without migration would have been a Europe devoid of human beings, although there would have been an impressive wealth of flora and fauna.

Not exactly rose-tinted glasses in this passage. Indeed, going with this view, one cannot say hooray for the current immigration to Europe. Most immigrants in Europe are more backwards culturally and technologically than the existing Europeans. They are not a conquering people, they are specifically invited in based on largely false premises (“we need workers”). This is not another “largely peaceful” takeover that improved the level of civilization in Europe, it’s a return to a less civilized stage, in the same way as when Germanic tribes overtook the declining Roman Empire (well, so we think).

The gradient principle holds true worldwide. There’s no break at the Urals or the Bosphorus, for instance—the geographical borders of Europe. On the other side of the Mediterranean, people don’t suddenly have completely different DNA. The gradual genetic shift occurs along the directions in which early modern humans spread out across the planet from sub-Saharan Africa. North Africans are therefore more closely related to Europeans and West Asians in genetic terms, not only because these regions were settled first by migrants leaving Africa, but also because there was plenty of genetic exchange. The differences between these populations and inhabitants of the Pacific region are bigger, then bigger again between them and the original inhabitants of North America, and biggest of all between them and those of South America, the part of the globe that was settled last by human beings. From East Africa to Tierra del Fuego, the general operative rule is that the smaller the geographic distance between two populations, the closer the genetic relationship. For the most part, ethnic minorities are no exception. Sorbs, for example, are genetically indistinguishable from the Saxons, Brandenburgers, and Poles around them, while the Basques are no different from some of the adjacent Spanish and French groups.

The delineations between these groups, apparent primarily through language, are due largely to cultural and political factors. Their coexistence makes society more diverse, but also occasionally more prone to conflict. Genetic justifications for ethnic conflicts have no scientific basis and should not persist in today’s world. It is on the grounds of unscientific claims made during the previous century that the field still has a reputation for smuggling in racist ideologies under the guise of genetic arguments. To the contrary, genetics today is less compatible with race-based thinking than ever before.

Krause must have been asleep at the watch. We already know that human genetic variation is not entirely clinal, and the examples he gives are plainly wrong. There are obvious and large discontinuities at mountain ranges, oceans, and deserts. Here’s a recent study (Peter 2020):

And zoomed in in various places of interest:

The brown color marks areas where genetic variation does not travel fast between (genetic barriers). We see some obvious big examples: the Saharan desert, the Mediterranean sea, the Himalayas, German vs. French border, the Alps, Germanic vs. Slavic border (broadly speaking).

sub-saharan africa is home to almost an eighth of the global population, more than 900 million people, and is host to a significantly greater spectrum of genetic diversity than anywhere else on Earth. This is where the family tree of modern humankind is rooted. Its branches spread right across the planet, but also across the vast continent of Africa, which today is home to the greatest number of humanity’s genetic forks and branches. The relationship between geographical and genetic proximity still holds, but there it’s on a much bigger scale than anywhere else on Earth. In concrete terms, the difference between the DNA of people in East and West Africa is roughly twice the size of the difference between European and East Asian DNA. From a genetic perspective, therefore, everyone on Earth is part of African diversity. The only thing distinguishing people outside Africa from those on the continent is their connection to the Neanderthals, and in Australia and Oceania the genetic influence of the Denisovans.

Despite these fundamental facts, Africa is wrongly viewed by many non-Africans as a singular, homogenous whole; this ignorance may stem from a global imbalance of power, which gives less voice and visibility to the continent’s countries and their diversity in the media, politics, and world economy. This diversity—unlike the diversity that exists in Europe—tends to be almost compulsively oversimplified even today. Though you no longer hear the term “Black Africa,” commonly used during the colonial era to refer to the area south of the Sahara, other terms with similar implications have replaced it. Inhabitants of sub-Saharan Africa and their descendants are referred to as “Black” right across the world, often as distinct from “white.” When the US census for the year 2000 asked what “race” its citizens belonged to, it classified all people descended from sub-Saharan African ancestors as “Black.”

Arguably, this grouping into various types is not racist per se; often it simply expresses the human impulse to classify and delineate. Yet requiring human beings to sort themselves by skin color is a way of showing how pointless the question should be. The average Irish person has obviously paler skin than, say, someone from southern Italy, yet both are considered “white.” Similarly, dark-skinned individuals from Sardinia or Anatolia can be difficult to distinguish from South African Khoisan people in terms of their skin color, while it would seem bizarre to a Khoisan to compare their skin tone to that of, say, a Congolese. Yet both of the latter are considered “Black.”

It’s the same fallacy as usual. Greater overall genetic variance is not generally that important because it may be largely non-functional. Would Krause argue that Jews, French Canadians, and Finns are particularly unimpressive peoples because of their very low genetic diversity? So far, there are no established differences between African groups in terms of polygenic scores for socially valued traits (intelligence, education, income, etc.). As such, from a perspective with interest in social status and human capital, there is little reason to care about the vast trove of largely non-functional African genetic diversity that the rest of humanity has lost to the bottleneck effect from the out-of-Africa expansion. The exception to the above claim are the differences between paleo-Africans (Bushmen, San etc.) and mainline Africans (Bantus etc.), where the latter are higher in polygenic scores for education and intelligence, in agreement with their phenotypic scores (Piffer 2021). There doesn’t seem to be much difference between, say, Nigerians and Ethiopians or Congolese.

Calls for national isolation have come back into vogue in recent years, completely independent from or even in inverse proportion to the actual pressures of immigration or the number of foreigners within a population. Nationalist and right-leaning populist parties are increasingly being given a share in government; in the European Parliament they’ve formed their own faction. Usually their sole points of agreement have to do with rejecting migration and avowing some vague notion of a “Europe of nations,” an “ethnopluralistic” community in which individual countries have sharply defined borders. Most object not only to immigration into Europe but also to the idea of mobility—the construct of a separate, clearly delineated “people” functions only if every group accepts that delineation. In this sense, an aversion to individuals who are considered too cosmopolitan is understandable, because such cosmopolitanism is attributed to a lack of fidelity to one’s homeland. One politician in the German parliament implied precisely this in 2018, accusing this “globalized class” of controlling information and thereby setting the “cultural and political agenda.” Possibly without realizing it, he also made a genetic reference when he called this mobile class of “digital information workers” its own “species.”

Such derogatory references to human mobility and internationalism often carry unmistakably anti-Semitic undertones. Hannah Arendt saw this attitude toward “cosmopolitanism” as one of the factors behind the Nazis’ relentless hatred of the Jews. Jews, according to Arendt, represented for the Nazis a supranational network, united by genetics and their status as a “chosen people,” exercising their power in individual countries without loyalty to any one in particular.

Though the idea of “Jewish genes” has long since been refuted, it’s still widespread. In 2010, for instance, the author Thilo Sarrazin said in a newspaper interview that “all Jews share a specific gene.” Sarrazin had misunderstood something fundamental. Many Ashkenazi Jews—those members of the religion whose forebears have lived for centuries in Central and Eastern Europe—do have similar genetic components that can be traced back to their ancestry from the Near East and to genetic mixing with Central and Eastern Europeans. Strict conventions around marriage meant that for centuries Jewish people usually only had children with other members of their faith, preserving a genetic signature that was distinct from the non-Jewish population. The result, however, was not a specific gene that all Ashkenazi Jews share but a special mixture of genes—the components of which originate from Eastern Europe and the Near East—that tends to appear in Ashkenazi populations more frequently. But the Eastern European components of Ashkenazi DNA are also found in the genomes of people from such regions as Thüringia, Saxony, and Brandenburg in Germany, and even their Near Eastern component is closely linked to the Anatolian farmer component that accounts for more than half of a Central European genome.

To paraphrase: 1) ideas of Jewish genes have been disproven, and 2) also here’s the recent evidence showing that Jewish genes is a thing. ??? In any case, the Nazis clearly did not believe in a singular Jewish gene. If they did, Nuremberg laws wouldn’t make any sense. If it’s about a specific gene, then people who had 1/2 or 1/4 or 1/8 Jewish heritage might have gone free (depending on the specific assumed model). As regards Sarrazin, it seems he was mainly summarizing the Ashkenazi theory of natural intelligence for a German audience in 2010, which is clearly a polygenic selection theory, not about a single gene.

while no serious scientist these days would still claim that national, religious, or cultural borders are determined by genetics, there is less consensus when it comes to other issues. One of these is whether there are genetically determined levels of intelligence that vary across diverse parts of the globe. A few years ago one geneticist caused a furor when he made a statement supporting this thesis: James Watson, Nobel Prize–winning codiscoverer of the structure of DNA, said in an interview in 2007 that Africans were less intelligent than Europeans. All the tests that had been conducted to prove the opposite, he claimed, had “not really” shown that. He couldn’t point to a demonstrable genetic difference, of course, but seemed convinced that one would soon be identified. After the scandal triggered by these remarks, Watson said he’d been misunderstood. He insisted that he simply wanted to make clear that there were genetic differences between populations and that components would soon be identified in specific populations—not, he suspected, among dark-skinned populations—that contributed to higher levels of intelligence.

Watson’s prognosis is still unfulfilled, and will probably remain so. In recent years, tiny portions of the genome whose presence is correlated with higher intelligence have in fact been identified, but these genetic components are only one part of the puzzle. Nor are these components unique to particular geographical areas: the gene variants that support intelligence are evenly distributed all across the world. This doesn’t preclude the possibility that a segment of genetic code will eventually be found that gives a higher-than-average number of people from particular regions or descended from particular origins greater intelligence, but this is highly unlikely. Millions of genomes have already been mapped out and countless intelligence tests conducted. If certain groups had higher levels of genetically determined intelligence, we would know by now

A hilariously bold and incorrect statement. Indeed, such differences have been studied since 2013, which was the first year a GWAS for education/intelligence was published. Here’s all the main studies of polygenic score gaps for intelligence or education:

Several more studies are on the way.

Generally speaking, genetic dispositions should not be overemphasized. New information uncovered in recent years about the impact of genetics on body height testify to this. Roughly a hundred gene segments influencing body height have been identified, many of which vary across regions. Far more important, however, are environmental conditions. In many parts of the world, today’s humans are a head taller than their grandparents, and this is due solely to better nutrition. Nobody would suggest that this height difference has emerged as a result of genetic changes within three generations. Similarly, it’s not true that more people these days have an “intelligence gene” simply because they would perform better than average on an intelligence test from 1950. Rather, the conditions for nurturing intelligence—such as education—have improved.

This does not mean, of course, that genes supporting intelligence are irrelevant to the development of someone’s personality. A person without these favorable prerequisites will probably find it harder to achieve good grades at school or university unless their disadvantage is balanced out by other factors, such as social status. Countless studies have consistently proved a connection between parental income and educational success.

Frankly, it’s problematic to conclude from comparisons of genetic traits and the results of intelligence tests that an “intelligence gene” exists at all. Intelligence is what intelligence tests measure. In other words, the current tests primarily reflect whatever society considers important. A correlation between high IQ and certain genetic components in particular populations would only prove that these populations are better on average at taking a particular test. If we were to use a different test as a benchmark, one tailored to the demands of another society, the same population might perform much worse while another did much better. There’d be no point pitting a high jumper against a 100-meter runner in a sprint, for instance, because it would tell you nothing about which one is more athletic.

What we now know about the impact of genes on intelligence contradicts hypotheses about regional or even national discrepancies, but it certainly does not render ethical debates superfluous. If genetic research can identify in a relatively short span of time segments of DNA that influence intelligence, then in the coming years and decades our understanding of this nebulous quality will be significantly expanded and deepened. We can already pick out certain autistic or schizophrenic personality traits in DNA. Nobody can predict what kind of personality profile will be mappable by DNA in the future. What will we do when for a few euros or dollars we can determine not only medical risks but also character traits? As vast sums of money are being poured into genetic research, humanity faces a difficult task in answering this and other highly complex ethical questions, though we are on the verge of being presented with a fait accompli. In 2012, the China National GeneBank was established with the express purpose of decoding not merely the human blueprint but that of the entire biosphere. Meanwhile, a major shareholder in 23andMe, one of the world’s largest private genetic-testing firms, is the data company Google.

Everything is more or less wrong. He is very naive about correlations between family measures and children’s intelligence. Does the possibility of reverse causation not occur to him? Smarter people have smarter children for largely genetic reasons, and smarter parents having higher incomes, so parental income will be positively correlated with children’s intelligence scores. Not exactly a mystery. This kind of ignorance is unfortunately the norm among population geneticists, as they generally don’t read the literature in behavioral genetics. No one has been talking about an intelligence gene since the 1920s (except for Volkmar Weiss, a fringe figure), so why bother attacking this strawman?

For the record, intelligence is not defined by what the tests measure. Historically, this is confused. Theoretical work on intelligence began 50+ years before any useful intelligence test was created (first tests around 1900, theoretical foundations from 1850s by Spencer and Galton). He seems entirely ignorance of the g factor and the positive manifold among every kind of mental test. Indeed, it can be shown that the various different schools of psychology have produced tests based on their own frameworks, but it turns out these all measure the same intelligence. A recent paper on this is Lasker (2022) but Dalliard (2013) is an excellent review.

Overall I liked the book. Hopefully someone will have a chat with Krause and point him in the right direction on some of his misunderstandings.

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